{
\def\sym#1{\ifmmode^{#1}\else\(^{#1}\)\fi}
\begin{tabular}{l*{5}{c}}
\toprule
                                &\multicolumn{5}{c}{\shortstack{log(Bid price)}}                                                              \\\cmidrule(lr){2-6}
                                &\multicolumn{1}{c}{(1)}         &\multicolumn{1}{c}{(2)}         &\multicolumn{1}{c}{(3)}         &\multicolumn{1}{c}{(4)}         &\multicolumn{1}{c}{(5)}         \\
\midrule
log(Emissions as bid)           &      -0.100         &      -0.143\sym{**} &      -0.269\sym{***}&      -0.609\sym{***}&                     \\
                                &     (0.061)         &     (0.063)         &     (0.084)         &     (0.087)         &                     \\
\addlinespace
log(Emissions as bid) $\times$ cyclone / bag filter&                     &                     &                     &                     &      -0.707\sym{***}\\
                                &                     &                     &                     &                     &     (0.169)         \\
\addlinespace
log(Emissions as bid) $\times$ scrubber / ESP&                     &                     &                     &                     &      -0.566\sym{***}\\
                                &                     &                     &                     &                     &     (0.095)         \\
\addlinespace
log(Plant total heat output)    &       0.087\sym{**} &       0.138\sym{***}&                     &                     &                     \\
                                &     (0.041)         &     (0.048)         &                     &                     &                     \\
 
Period FE                       &                     &         Yes         &         Yes         &                     &                     \\
Plant FE                        &                     &                     &         Yes         &                     &                     \\
Plant $\times$ Period FE        &                     &                     &                     &         Yes         &         Yes         \\
                                &                     &                     &                     &                     &                     \\
p-val: $ H\textsubscript{0} $: No unobserved heterogeneity&                     &                     &                     &       0.000         &       0.000         \\
p-val: $ H\textsubscript{0} $: No observed heterogeneity&                     &                     &                     &                     &       0.468         \\
R\textsuperscript{2}            &        0.01         &        0.07         &        0.26         &        0.46         &        0.46         \\
Plants                          &         146         &         146         &         146         &         146         &         142         \\
Observations                    &        3120         &        3120         &        3120         &        3120         &        3082         \\
\bottomrule
\end{tabular}
}
